The game was released to start off the 15th anniversary of the release of the Sonic the Hedgehog series. For a short while, also to celebrate the anniversary, the Microsoft Xbox version of the game was released with a free Sonic X DVD, which contained five episodes from the first and second seasons. This stopped after the Xbox version failed to sell well. This game introduces five new playable characters, the Babylon Rogues and the E-10000 series. A sequel to Sonic Riders, entitled Sonic Riders: Zero Gravity, has been released in 2008 for the Wii and PlayStation 2. This was the last Sonic the Hedgehog game for the Nintendo Gamecube and Microsoft Xbox.